Assuming everything else was the same, but we branch off into a parallel universe where the US Supreme Court just ignore facts and arbitrarily decided by a 5-4 vote (assuming Roberts side with the 3 liberal justices, because that’s probably the most realistic scenario) that Donald J. Trump is the winner of the election. What would happen? Civil war?
Asking because I’m a pessimist and always think of worst-case scenarios.
But they didn’t decide it directly and arbitrarily, as OP is suggesting might have happened. The power to elect the President is in the hands of the Electoral College, and the House of Representatives. The most that a Supreme Court can do is tamper with the process of tallying the popular vote.